The present invention relates generally to shoe insoles, and more particularly, to improved insoles particularly adapted for obese people.
According to an article "Demography, Obesity: A Growing Problem, " The Futurist, October, 1999, approximately 22% of adults in the United States are obese, with obesity defined by the World Health Organization as a body mass index greater than or equal to 30 Kg/m.sup.2.
The inventors herein designed and executed an investigative gait and foot morphology study to define the gait biomechanics and foot morphology of obese men and women. It was discovered that obese people exerted more load under the arch and lateral side of their feet during gait in comparison with individuals having a body mass index less than or equal to 25 kg/m.sup.2. Approximately 36% of the obese women subjects provided varying degrees of pes planus (flat feet), while approximately 43% of the obese men subjects provided varying degrees of pes planus (flat feet). Further, the frequency of moderate fatigue or discomfort in the foot, leg and lower back exceeded 50% in the male and female population. Still further, overall gait speed tended to be slower than that for that part of the population having a normal weight, that is, a body mass index less than or equal to 25 kg/m.sup.2.
From this study, it was determined that:
a) obese people have wider feet and put more pressure on the mid-foot and forefoot portions; PA1 b) obese people overpronate, tending to flatten or fall on the inside arch of the foot; PA1 c) obese people have a tendency to walk with their feet wider apart, and this, in combination with the overpronation (flat feet), prevents normal foot motion during walking; and PA1 d) obese people tend to roll their feet outward during heel strike, thereby introducing an extraneous motion to the foot, in contrast to normal weight people who do not roll their feet during heel strike. This increases the loading in the lateral arch region during gait.